This invention relates to vehicular shock absorbers, and to an improved piston valving assembly for MacPherson type struts and cartridges.
U.S. Pat. No. 4,356,898 discloses a desirable shock absorber. This shock is desirable because it has piston valving adapted to accommodate relatively short and rapid wheel movement without ride harshness, as well as relatively long and slow wheel movement. The first such wheel movements occur on tar strips and the like, while the second such movements occur at roadway intersection dips and the like. The effect of the valving is to reduce the damping forces at low piston velocities and short strokes without reducing the damping forces at high piston velocities at longer strokes. This in turn decreases ride harshness by reducing the forces that are transmitted by the shock absorber through the suspension system to the vehicle occupants during the aforementioned short wheel movements produced by tar strips and expansion joints. The damping forces at the beginning or initiation of long wheel excursions are also reduced. In the latter case, full damping forces at the higher velocities can still occur, but the rapid build up of those forces at the beginning of such wheel movement is reduced.
The valving of U.S. Pat. No. 4,356,898 is especially suited to twin tube shocks, which traditionally and exclusively have relatively small diameter piston rods. The valving is not suited to MacPherson type struts and cartridges with large diameter piston rods.